Creation

The seat was created for the general election in February 1974. It comprised the southern part of the former Rural District of Amersham, including Amersham and the Chalfonts, previously part of the abolished constituency of South Buckinghamshire; and Chesham and the northern part of the former Rural District of Amersham, transferred from Aylesbury.

Political history

Until the 2021 by-election was won by the Liberal Democrats candidate, the previous general election results in the seat since its creation had seen a Conservative winning margin of between 10,416 (Feb 1974) and 23,920 (2015) votes, in each case an absolute majority of the votes cast. In each of the general elections except two the Liberals, or subsequently Liberal Democrats, had come second, with results as high as 31.15 per cent of the votes cast. Labour came second only once, in 2017, when it achieved its best ever result of 20.6 per cent. UKIP came second in 2015, Labour in 2017 and the Liberal Democrats in 2019.

In June 2016, an estimated 55 per cent of adults voting in the EU referendum in the constituency voted to remain in the European Union, compared with 48% in the UK as a whole. The estimated turnout of 83.6 per cent was the highest in any constituency in the UK, the only higher turnout in the referendum being in Gibraltar.^[4] In the 2019 EU Parliament elections more than 50 per cent voted for parties supporting continued UK membership of the EU, although the turnout was only 42.8 per cent. The pro-EU Liberal Democrats were the most popular party with 31.9 per cent, with the pro-Leave Brexit Party in second place on 30 per cent.^[5] Despite the seat's support for remaining in the EU, its pro-Brexit MP, Dame Cheryl Gillan, was re-elected in both generals elections held after the 2016 referendum (in the case of 2017 with her highest vote share since her first election in 1992), albeit with slightly reduced majorities.

Dame Cheryl Gillan MP died in office on 4 April 2021, and the seat was gained by the Liberal Democrats’ pro-EU Sarah Green in the subsequent by-election on 17 June 2021 with a majority of 8,028 votes.^[6] The Liberal Democrat win in the 2021 Chesham and Amersham by-election was seen as an upset in a historically safe Conservative seat,^[6] and party leader Sir Ed Davey tweeted that the result had "sent a shockwave through British politics".^[7] It was the first in a series of likewise safe Conservative seats that were lost to the Liberal Democrats through by-elections in that Parliament.

In December 2023, the Labour Party included the seat in its published list of 211 non-battleground seats, suggesting they did not see it as winnable.^[8]

Proposed

Further to the 2023 Periodic Review of Westminster constituencies, enacted by the Parliamentary Constituencies Order 2023, from the next general election, due by January 2025, the constituency will be composed of the following (as they existed on 1 December 2020):

• The District of Buckinghamshire wards of: Amersham and Chesham Bois; Chalfont St. Giles; Chalfont St. Peter; Chesham; Chess Valley; Chiltern Ridges (polling districts CD and CDA); Denham (polling district SGE); Gerrards Cross (polling districts SGN and SGS); Hazlemere; Little Chalfont and Amersham Common; Penn Wood and Old Amersham.^[13]

The boundaries will be similar to those of 1983 to 2010, with Great Missenden now being included in the newly created constituency of Mid Buckinghsmshire and Hazlemere being returned from Wycombe. In addition, the town of Gerrards Cross will be transferred from Beaconsfield.

Elections in the 2020s

Cheryl Gillan died on 4 April 2021,^[14] triggering a by-election held on 17 June 2021.^[21]

Elections in the 2010s

Elections in the 2000s

Elections in the 1990s

Elections in the 1980s

Elections in the 1970s